Electronic equipment, such as computers and cellular telephones, typically contain various circuit boards that in turn contain electronic components that are interconnected via metalized circuitry on the circuit boards. Electrical connectors are frequently used to interconnect a circuit board to other circuit boards or to other components of the equipment. With the continuing advance of electronic technology, the individual components of the electronic equipment are made smaller resulting in miniaturized but highly dense packages. Circuit board technology has similarly migrated toward smaller and thinner structures. When a connector is surface mounted to a circuit board, the contact leads of the connector must be brought into mated engagement with respective solder pads on the circuit board and held there during soldering. Typically, solder paste is applied to the solder pads on one side of the circuit board and a connector and electrical components placed in position with their leads embedded in the solder paste and in contact with the pads. The circuit board is placed in a fixture which is then placed in a furnace and subjected to heat to reflow the solder and complete the electrical connection between the leads of the connector and the circuitry. If the circuit board is double sided it is then turned over and the process repeated so that a connector and components are soldered to circuitry on both sides of the circuit board. By way of example, as shown schematically in FIG. 1, a circuit board 10 is supported at its edges 12 and 14 by a fixture 16. A prior art electrical connector 18, shown in plan view in FIG. 2, is in position on the top surface 28 of the circuit board, prior to soldering, and another similar connector 19 that had been previously soldered in place is on the lower surface 30. The connector 18, in the present example, includes an insulating housing 20, four leads 22 from power contacts and several leads 24 from signal contacts, contained within the housing. Three mounting clips 26 are arranged in openings in the housing so that they are flush with the bottom mounting surface of the housing. FIGS. 3 and 4 are enlarged views of a portion of the circuit board 10 shown in FIG. 1. As shown in FIG. 3, when the circuit board is quite thin it will sag downwardly a substantial amount while it is being supported by its edges. This results in the top surface 28, against which the connector 18 is resting, being concave. This concave condition of the circuit board may also be aggravated by distortions caused during the manufacture of the circuit board. When the connector 18 is moderately long the leads 22' and 24' and the clip 26 near the center of the connector may be sufficiently spaced from the surface 28 so that they will not be soldered to their respective solder pads during the soldering operation. Additionally, the connector 19 which was previously soldered to the surface 30 when the circuit board 10 was reversed, will now be on the lower side of the circuit board, as shown in FIG. 4. Since the circuit board 10 sags downwardly the lower surface 30 is convex. When the circuit board is again heated to reflow the solder paste on the upper surface 28 the solder on the lower surface 30 will melt causing the leads 22' and 24' and the clips 26 near the ends of the connector 19 to lift off of the surface 30. If the space between the leads and their solder pads is great enough the solder will separate, due to surface tension, and there will be no electrical connection upon completion of the soldering operation. Additionally, the reduced contact with the melted solder yields less holding force due to surface tension, therefore, the connector 19 may fall off of the circuit board while soldering the connector 18 in place. While the particular prior art connector 18, in the present example, has the above described problems, so too do other similar connectors that are rather long and intended for mounting to relatively thin flexible circuit boards that are supported at their edges during soldering.
What is needed is an electrical connector that will conform sufficiently to the curved surface of the circuit board so that the leads remain sufficiently close to their respective solder pads to assure a good soldered connection and, to provide sufficient area in contact with the melted solder to retain the connector in place on the under side of the circuit board when a connector is being soldered on the upper side.